Atheism cannot be classified as a single category, but as a group of categories.
There can be the atheist who has convinced himself through a thought process, another is an atheist, because he has refused everything that could have persuaded him otherwise, and this has led him towards atheism. There is also the person who doesn’t consider the problem at all, he avoids it rather that make a choice. There is the atheist full of doubts, who could be defined better as an agnostic. There was in certain historical periods, and there still are, and there are many of them, even the atheist who is so just for convenience, or because it is fashionable, and could give some success and visibility.
Why is it that the person who defines himself as an atheist is without the urge to do further research, why does he not feel the need to understand something more.
Mainly it could be the fear of finding something that rationally he cannot explain or understand as it is not tangible. When we talk of God, Energy, and energetic Evolution, the totally rational person will feel lost as he cannot find the proof that he needs, and as it makes him feel insecure, he avoids thinking about it.
Another case could be in the parallel dimensions ( here we pick up the discussion about the Multiverso) where the individual could be an extremist or even a being completely dedicated to the Spirit, who needs to “compensate” through a Life where the Spirit is excluded from his thoughts.
Therefore we can see that we must always refer to the individual when discussing atheism.
Now I wish you to try this: talk to a person who declares himself an atheist, reason with him, and try to take the discussion as far as it is possible.